An embodiment of the present invention relates generally to control circuits for use with standard dimmer switches, and more particularly, to an LED driver circuit for use with standard incandescent phase control dimmers.
With the rising costs of energy, the search continues for lighting solutions that consume less power and operate at a lower cost. Compact fluorescent light (CFL) bulbs were thought to be one energy efficient answer. However, CFLs contain a small amount of mercury (Hg), which makes disposal rather difficult since the bulbs cannot simply be thrown in the garbage. Additionally, the mercury from broken CFLs can present a health hazard if not promptly and properly cleaned up. The Environmental Protection Agency (EPA) has issued guidelines for cleaning up and disposing of CFLs.
Light emitting diodes (LEDs) are increasing in popularity. Significant advances have been made in LED technology to produce higher power at less initial cost to the consumer. LEDs last longer, are more efficient, and produce less heat than traditional incandescent light bulbs. LEDs also contain no mercury.
One disadvantage of LEDs results from the nature of the diode, that is, the LED will only emit light when current flows in the correct direction. Accordingly, LEDs cannot just be directly connected to an alternating current (AC) source without experiencing blinking or flickering at the frequency of the AC source. The problem is compounded when the AC source is dimmer controlled by, for example, a phase control dimmer, which switches off parts of each cycle from the AC source.
It is therefore desirable to provide a dimmable LED driver that does not require replacement of previously installed conventional dimmers. Ideally the driver is of a simple and small design, while still being efficient when dimmed.